Question

A common sight in our modern world is high-voltage lines carrying electric energy over long distances from power plants to populated areas. The delivery voltage of these lines is typically 500 kV, whereas by the time the energy reaches our households it is down to 120 V (see Chapter 20 for how this is done).
(a) Explain clearly why electric power is delivered over long distances at high voltages when high voltages are known to be potentially C lethal.
(b) Calculate the ratio of electric current in the wires (assumed ohmic) at 500 kV to when the wires operate at 120 V.
(c) Calculate the ratio of heating loss in a given length of wire (assumed ohmic) carrying current at 500 kV to when it operates at 120 V.